He said the magnitude of the development — which will be the city’s priciest residential condominium to date — made walking away more difficult. But Karadus said he was unhappy with the daily grind of working in-house for a developer, and missed his resale business too.

“This was a very corporate position and I gave it six months,” he said.

Extell could not be reached for comment.

Karadus, a veteran broker with more than 20 years in the business, joined Gary Barnett’s firm in August to lead sales at the 95-story supertall, which has a projected sellout of $4 billion.

At Town, he and Ginger Brokaw led sales at the Charles, a 31-unit condominium, where they brokered several record-breaking deals, including the sale of five penthouses for $58.6 million.

Both Karadus and Brokaw later moved to BHS, and Karadus spent a year at the firm before taking the in-house marketing job at Extell.

“I really do believe in the project, and I believe in luxury,” he said. “I look forward to selling this project — but from the outside.”

Extell Development’s Gary Barnett closed on $1.14 billion in financing for the project earlier this year, when it finalized a $900 million construction loan from a consortium led by JPMorgan Chase. The developer also secured $235 million in preferred equity from an unnamed hedge fund. Terms of the loan give Extell three years to sell $500 million worth of condos.

The planned 95-story super tall, located at 217 West 57th Street, will have 179 units, including at least 20 priced over $60 million. The priciest listing is asking $95 million, but three of the largest units don’t have prices. The top penthouse spans 15,898 square feet and features a private, 58-foot ballroom.